# ANSI/IEEE single-phase autotransformer symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-single-phase-autotransformer
Publisher: Elora Grid
Updated: 2026-10-14
Lookup label: AT 1PH
Drawing use: SLD, Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: Autodesk IEEE-oriented Transformers functional form
Autodesk explicitly publishes this block under IEEE Symbol Preview. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Related representation: [Single-phase autotransformer](https://eloragrid.ai/symbols/single-phase-autotransformer)

IEEE-oriented graphical reference for single-phase autotransformer, with public vendor evidence and drawing-reading notes.

## What it represents

The single-phase autotransformer form identifies a shared winding path between input and output. Following that common electrical path explains why this device differs from two electrically separate windings even when the voltage transformation purpose is similar.
This is a convention-specific lookup based on the publisher's IEEE-labelled preview. The geometry here is independently drawn to explain the connection or operation; it is not a certified reproduction of the standard graphic.

## How to read it

- Locate the common winding terminal and the load tap.
- Read the selected library and the project legend together. A vendor block identifier is meaningful within its named library and is not a universal standard-symbol code.

## Information to show or reference

- State input/output voltages
- Show common connection
- Reference tap ratings

## Important distinction

An autotransformer does not provide the same winding separation as a two-winding transformer.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview — Transformers
- Public vendor block name: HXF1P1AUTO (Autodesk identifier; not an IEEE symbol number)
- Standards context: IEEE/ANSI 315-1975 covers diagram graphics. IEEE lists this edition as Inactive-Reserved.
- Artwork scope: Original functional illustration; exact standard glyph and compliance are not certified

## Public references

- [Autodesk IEEE Symbol Preview — Transformers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-68D02867-7A98-47D1-A83F-DBAD1DDB616F.htm) — Autodesk. Exact public IEEE-oriented category page verifying the component name and vendor block identifier.
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/) — IEEE Standards Association. Graphic-symbol standards context and official status; not a source of reproduced artwork.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.